Communications engineers face a number of challenges today, including maximizing the amount of information that can be communicated over the limited resources available. With limited frequencies available over which to communicate radio signals, and with the amount of information that people wish to communicate growing rapidly, it is important to use the available:frequencies as efficiently as possible. In order to do so, it is necessary to provide means by which signal interference can be reduced to minimum levels in order to allow modulation of a maximum amount of information onto signals that are transmitted over those frequencies.
One area that has been of interest is that of satellite communications, especially satellite communications for delivery of media for consumer consumption, such as television signals, or the like. As the number of satellites increase, the spacing, or separation between satellites decreases, and the increase in demand for more and more content to be delivered from the same or multiple satellites, interference between the satellite signals has become an issue.
One type of interference is due to the reception of signals transmitted from a first satellite at the same frequency or frequencies as signals received from a second satellite. If a receiver receives both signals without being able to sufficiently discriminate between them, the signals will interfere with one another. This is commonly referred to as cross-satellite interference. The closer the spacing between the satellites, the more cross-satellite interference may occur. Conversely, the wider the antenna beam-width (which is equivalent to lower antenna gain, i.e. a smaller antenna dish size), the more potential cross-satellite interference.
Another type of interference is due to signals on a first polarization of a first satellite being transmitted at the same frequency as desired signals on a second polarization of the first satellite. If the receiver receives both and cannot sufficiently discriminate between the two, then each will interfere with the other. This is referred to cross-polarization interference.
One way by which cross satellite and cross polarization interference can be reduced is to put as much separation as possible between each pair of potentially interfering signals. Such separation may be, for example, by separating the signals by frequency, physical distance, or the like. However, separating signals in these ways can reduce the amount of information that can be transmitted between a transmitter and a receiver, because the efficiency with which information can be transmitted over the communication system may be diminished. Accordingly, it would be desirable to have effective means capable of reducing the amount of cross satellite and cross polarization interference.